1. Field of the Invention
The present invention relates to food supports, such as, for example, sleeves, boxes, and trays that can be used for heating or reheating food in a microwave oven, and in particular to supports that include a microwave susceptor material that heats when exposed to microwaves so as to be effective in browning and crisping the food product.
2. Description of Related Art
It is known to provide a substrate with a microwave susceptor material so that the substrate can be used as a tray or wrapping for reheating, and possibly browning and crisping, food products. U.S. Pat. No. 4,825,025 to Seiferth discloses a disposable food receptacle (i.e., a tray or a sleeve) for use in microwave cooking that includes a microwave susceptor material so as to brown the exterior of a food product placed in the receptacle. A thin layer of an electrically conductive material, such as an elemental metal is incorporated into the receptacle on the food contacting surface thereof, so that the conductive layer will become heated by the microwave radiation and will, in turn, brown the exterior of the food in the receptacle. The conductive layer is formed as an extremely thin film deposited on a substrate protective layer by a process of vacuum vapor deposition.
U.S. Pat. No. 4,267,420 to Brastad also discloses a flexible wrapper comprised of a plastic film or other dielectric substrate having a very thin coating thereon of an elemental metal such as aluminum.
It is known to provide circular microwave susceptor trays for use with food products such as, for example, pizza pies, so that the pie will be prevented from becoming soggy during microwave heating. The tray contains a microwave susceptor material, such as the materials described in the above-referenced patents, which heats when exposed to microwave energy. The heated tray causes the bottom surface of the pie to brown and become crisped, thus improving the texture of the food product.
While these trays work well with whole pies, when a person chooses to heat only a portion of a pie, the entire tray must be used to support the pie portion in the microwave oven. This results in portions of the tray being entirely exposed (i.e., uncovered by the food product) during microwave heating. The portions of the tray that are not covered during microwave heating become very hot because there is no food product abutting them to absorb the heat from these portions of the tray. These very hot portions can warp or even melt (the susceptor typically is laminated to a plastic protective layer) due to the excessively high temperatures generated therein. This wastes susceptor material, which is relatively expensive compared to the overall cost of the product.
In addition to trays, it is desirable to provide a microwavable substrate in a form that is easy to use with variously sized food products.
U.S. Pat. No. 5,220,143 to Kemske et al. discloses susceptors having disrupted regions for differential heating in a microwave oven. The susceptor consists of variable sized conductive areas whose size is adjusted to compensate for undesirable non-uniform heating patterns. FIGS. 26 and 29 show a susceptor pad having radially inward extending cuts. The cuts are provided so that food products placed near a center of the pad brown equally to those placed near an edge of the pad. The pads of Kemske et al. have large sized susceptor areas in the center region and relatively smaller sized susceptor areas in edge regions. It is believed that the cuts provided in the pad only are located in the surface of the pad to extend through the susceptor layer, but do not extend through the entire pad. Accordingly, Kemske et al. does not recognize the problems addressed by the present invention.
U.S. Pat. No. 4,940,867 to Peleg discloses a box for holding a microwaveable food product. While the box includes a tear strip, the tear strip does not enable the box to be split into smaller portions that are useful with portions of the food product supplied therewith.
U.S. Pat. No. 4,870,233 to McDonald et al. discloses a tray/susceptor combination for use in a microwave oven in which an upper susceptor unit, which overlies the food product, includes a series of longitudinal slits forming a fold line to provide a flange. A series of venting slits also are provided to enable steam and vapors to be vented through the susceptor. McDonald et al. also does not appreciate or address the problems solved by the present invention.